Numerous apparatus have been used in the past to sever pipe or tubing to desired lengths. An early cutter design is shown in U.S. Pat. No. 532,845 to W. W. Tucker which incorporates a rotatable head with angularly spaced support rollers and a radially translatable cutter wheel which may be adjusted inwardly against tubing positioned between the rollers and the cutter wheel. This design does not permit the radial movement of the cutter during operation of the device and thus does not lend itself to ease and speed of operation.
A later design is shown in U.S. Pat. No. 3,772,945 to John F. Varga. This device also discloses a tube cutoff device having a rotatable cutter head with a central opening therethrough for feeding a tube into the cutoff device. The head is rotatable around the tube and the cutter is cammed radially inwardly by a sleeve to engage and sever the tube. The cutter is biased outwardly by a spring as are two angularly spaced tube support rollers. The camming sleeve is apparently not fixed relative to the head and thus may not only slide axially, but may have a tendency to move angularly relative to the head. The cam sleeve is controlled by a single cam roller which engages a follower groove in the cutter of the sleeve. This structure is subject to binding and excessive wear between the cam roller and the follower groove, as well as between the camming sleeve and the slide members on which the cutting disk and support rollers are mounted. While the patent to Varga is an improvement over the patent to Tucker, it does not provide an optimum design for a rotary cutter head of the type disclosed.